Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: Case series and a review of the literature

RATIONALE: Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare idiopathic disease with only about 100 cases reported in the literature. PATIENT CONCERNS: Here, we presented 4 cases of DIPNECH. Four patients included 2 females and 2 males, aged 54 to 64 years old; 3 had no smoking history and 1 had history of smoking for 30 years. Surgical resection was performed for every patient. Cases 1 and 3 did not receive postoperative chemotherapy or radiotherapy, and case 2 received 4 times of postoperative chemotherapy. Case 4 just finished the operation and after a period of time, he will receive postoperative chemotherapy. DIAGNOSES: Case 1: A 57-year-old female had chest pain, and computer tomography (CT) examination prompted a mass shadow of left lung lower lobe. Case 2: A 64-year-old female had cough and expectoration for more than 1 month. CT examination showed: a lump with diameter of about 2.5 cm and irregular edge was in right lung upper lobe, being largely possibly lung cancer. Case 3: A 54-year-old male, CT examination accidentally found a long strip-shaped nodule in left lung oblique fissure when checkup's, and he had no fever, cough, expectoration, chest tightness, or chest pain. Case 4: A 61-year-old male, checkup's CT examination accidentally found a nodule, fibrosis, bronchiectasis, and secondary infection in the left lower lobe. Combined with pathological morphology and immunohistochemistry, cases 1 and 3 were diagnosed as DIPNECH with multiple carcinoid tumorlet formation and chronic inflammation and bronchiectasis, case 2 was diagnosed as an adenocarcinoma with DIPNECH and multiple carcinoid tumorlet formation, case 4 was diagnosed as an adenocarcinoma with DIPNECH and multiple carcinoid tumorlet formation and chronic inflammation and bronchiectasis. INTERVENTIONS: Surgical resection was performed for every patient. Cases 1 and 3 did not receive postoperative chemotherapy or radiotherapy, and case 2 received 4 times of postoperative chemotherapy. Case 4 just finished the operation and after a period of time, he will receive postoperative chemotherapy. OUTCOMES: Four patients have been followed up and have had good condition. LESSONS: DIPNECH is often found accidentally in a surgical specimen, is easily missed, and needs careful observation. Immunohistochemistry is necessary to make this diagnosis.